It is known that when an orifice is placed in an energetic gas flow, such as an air stream, its edge gives rise to phenomena of turbulence which constitute sources of noise, the intensity of which varies with the flow conditions (the speed of the flow, the external temperature, the temperature of the gas, the angle of incidence of the flow with respect to the orifice, etc).
It is an object of the present invention to remedy this disadvantage by attenuating the noise produced by such an orifice positioned in a gas flow.